Field of the Invention
The present invention relates to telecommunications, and in particular relates to a method of selecting an active SIM from multiple SIMs and a wireless device utilizing the same.
Description of the Related Art
A multi-SIM (subscriber identity module) wireless device, including particularly mobile phones, personal digital assistants, tablet and laptop computers, mobile WiFi router and mobile USB dongle can hold two or more SIM cards. Each SIM card contains a unique international mobile subscriber identity (IMSI) and the related key which allow a user to be identified and authenticated by a service provider. Hereinafter “SIM” and “SIM card” will be used interchangeably. The multi-SIM wireless device allows a user to operate with a corresponding number of communications networks and/or arrangements without the need to carry two or more wireless devices.
Packet Switched (PS) communications service is delivery of data stream in form of sequences of packets. With growth of PS communications services, an increasing number of the multi-SIM wireless devices are equipped with multiple SIMs which subscribe to PS networks. For example, the same mobile phone can be used for business and private uses with separate numbers and bills on the same or different PS networks. In another example, the same mobile phone is used for travel, with one SIM being used in the home town and the other SIM being used in the place visited, provided by the same or different PS network operators. As another example, both SIMs may be used with the same PS network, for example, to increase a total bandwidth of data transfers on the mobile phone. In general, using multiple SIMs allows the user to take advantage of different pricing plans for PS data services to certain destinations, and/or to keep personal and business uses separate, and/or to achieve higher bandwidth, and/or to obtain coverage across different PS networks using the same mobile phone.
Because the multi-SIM wireless device contains multiple SIMs, a method of automatic SIM selection for a multi-SIM device is required.